On Dec 28, 7:14*am, wrote:
On Dec 27, 10:54*pm, lesnpat wrote:





On Dec 27, 5:31*pm, wrote:

On Dec 27, 5:41*pm, ransley wrote:

On Dec 27, 3:22*pm, wrote:

On Dec 27, 4:10*pm, lesnpat wrote:

My spa is a 2002 Regency Spas, made by National Equipment Mfg. Corp.
The circuitboard system has no mfr. name anywhere. *There are both a
knob thermostat control on the box at the heater and a topside
pushbutton control at tubside. *The heater is electric Vulcan style
(flow-through 2" stainless tube). *Pump is 220v and heater is 110v.

The spa heats normally, but quits short of target because the topside
digital thermometer reads 5 degrees warmer than actual water temp. *Is
there a way to calibrate the digital system to get the reading in sync
with the actual water temperature?

I have a much older NEMCO spa, but the system may be similar. *With
mine, the system of measuring and displaying the temp is controlled by
the electronics inside the power pack and it's not meant to be user
adjusted. * *There are several pots inside the power pack that control
parts of the settings. *One of them does what you want. *I figured it
out by experimenting years ago, but don't know which one was which
anymore. *Plus your power pack is probably different. * I couldn't
find any info avail that detailed what's in the power pack or how it
works.

Are you sure it's really a calibration problem? * Is it always off by
about 5 deg at all temps?

Why not set to where you are comfortable or 5 up- Hide quoted text -

- Show quoted text -

I think it depends on which way it's off. * If it reads 105, but it's
actually 100, then that could be a problem. *Spas are typically set to
go no higher than somewhere around 105. *If you want to get that last
5 deg out of it, you wouldn't be able to. * I like mine somewhere
around 104.

If it's off the other way, or he can live with whatever the incorrect
max turns out to be, then I agree, probably easiest thing to do is
live with it.- Hide quoted text -

- Show quoted text -

The differential is always the same, and the reading is off in the bad
direction. *The controls allow settings only up to 106, which means I
can't heat above 101 actual water temp. *Nice, but not best. *I won't
say I can't live with it, but in the wintertime warmer would be a lot
better.- Hide quoted text -

- Show quoted text -

If you decide you can't live with it, there are a few possible
solutions:

1 - You can call up the manufacturer or local dealer and see what they
say. *It's possible they have the info available or can adjust it with
a service call.

2 - It's possible changing the temp sensor would fix it, as that could
be the part that is off.

3 - You could disconnect the wires to the temp sensor. *Then use a VOM
to measure it's resistance at a couple of temps and see how it
changes. * From that you may be able to figure out how to put an
addional small resistor in series to trick it out by 5 degrees. * This
depends on whether the resistance goes up or down with temp, not sure
which it does

4 - You could open up the power pack. *You'll likely find 2 or 3
potetiometers inside. *One of them likely makes the adjustment you
want. * Carefully keep track of what you're doing and change one a 1/2
turn at a time and see what happens, until you find the right one.
That's what I wound up doing on my old NEMCO when I ran into a similar
problem. *If you do that, keep in mind that you may see the display
change even when you're not on the pot that really adjusts what you
want. * *For example, there might be one that fiddles with the
linearity over the temp range, or similar that will cause the display
to read differently when you screw with it. * I think mine had 3 pots.- Hide quoted text -

- Show quoted text -

The Mfr. of the tub is apparently no longer in business, and I'm in a
rural spot where a service call would be pricey in any event. I
thought of replacing the sensor, but couldn't see any way a defect
there could give a high reading. But, your third and fourth items
look good. The spa's outdoors, so it will have to wait until better
weather. I'll let you know the results.